You may have a mom or dad that have passed, and the surviving spouse has someone new in their life. A variety of losses may be surfacing (loss of family as you knew it or loss of connection with the living parent); anger (how could my parent do this) or questions (were my parents not in love?).
Take all the emotions and questions that are surfacing to the Lord. He knows your heart and the circumstances. Ask God to take away any ill feelings toward your parent and the new person in your parent’s life and ask Him to show you what you cannot see.
“Cast your burden on the Lord, And He shall sustain you; He shall never permit the righteous to be moved.” Psalm 55:22
The Bible does encourage remarriage (1 Corinthians 7:8-9; 1 Timothy 5:14). However, it does not condone living together; fornicators will not inherit the kingdom of God (1 Corinthians 6:9-10).